Regional Hazard Research Articles

Seismic hazard analysis and financial impact assessment of railway infrastructure in the US West Coast: A machine learning approach.

This research examines the seismic hazard impact on railway infrastructure along the U.S. West Coast (Washington, Oregon and California), using machine learning to explore how measures of seismic hazard such as fault density, earthquake frequency, and ground shaking relate to railway infrastructure accidents. By comparing linear and non-linear models, it finds non-linear approaches superior, particularly noting that higher fault densities and stronger peak ground shaking correlate with increased infrastructure accident rates. Shallow earthquakes with magnitudes of 3.5 or greater and hypocentral depths <20 km also exhibit a pronounced correlation with the incidence of railway infrastructure accidents The study extends to financial impact analysis through Net Present Value and Monte Carlo Simulation, and evaluates damage costs from 2000-2023 to guide financial planning and risk management strategies. It highlights the crucial role of advanced financial tools in optimizing maintenance and long-term planning that could result in better preparedness in high seismic hazard regions and emphasizes the need for robust risk management strategies in enhancing railway operational safety that considers the local and regional tectonic and seismic activity and local ground shaking intensity.

Flood Monitoring and Mapping in the Ghatal Region of West Bengal, India

Abstract The Ghatal block of Paschim Medinipur district in West Bengal, India experiences frequent flooding due to the overflow of the rivers Dwarakeswar, Rupnarayan, Shilabati, and their tributaries. Although the Ghatal master plan was prepared and the foundation stone was placed in 1982 to reduce the flood vulnerability in this region, the plan is still not being implemented. To determine the flood vulnerability in the Ghatal block, very few research investigations have been carried out. The previous studies just applied a successful scientific methodology to evaluate flood risk; they did not engage in participatory research with local community perception. Hence, a thorough investigation is needed to manage floods in a way that increases community resilience. Using a comparative review and the geographic information system (GIS), the study seeks to identify the flood-prone locations in the Ghatal block, which is essential for flood management in any region. The article uses a multi-criteria analysis to pinpoint probable flood hazard regions. Seven parameters are used in the study to carry out the multi-criteria analytical hierarchy procedure. Based on their relative importance for the event, the criteria’s weights are determined using the Analytical Hierarchical Process (AHP) method, and a Suitability Index is prepared. The index indicates that the severe problem of river flooding in the Ghatal block of Paschim Medinipur needs to be looked after on an urgent basis and with path-breaking solutions, especially for the Ghatal municipality and the various gram panchayats such as Irpala, Mansuka-I, Monoharpur-I, Ajobnagar-I, Mohonpur, Dewanchak-I and the North-Eastern part of Sultanpur and the Southern part of Dewanchak-II.

Thermo-mechanical analysis and creep lifetime prediction of coated turbine vanes considering thermal barrier coating spallation characteristics

Quantitative analysis of the influence of thermal barrier coating spallation on the thermo-mechanical behaviors and creep lifetime of turbine vanes is crucial for their maintenance and reliability improvement. The temperature and stress distribution of vanes with preset coating spallation damage are investigated in this study, using the thermal-fluid-solid coupling method. Additionally, a further computational analysis is conducted to predict the hazardous regions and creep lifetime of the vanes. The results indicate that coating spallation leads to significant changes of the temperature and stress distribution at the spalled regions of vanes. The remaining coating on the unspalled regions continues to provide effective protection. Stress concentration primarily occurs at the upstream and downstream of the leading edge film holes, while high-stress regions are observed between adjacent rows of film holes, forming a serrated shape. The creep lifetime of the vanes decreases significantly at the region with coating spallation. When the same spallation area is considered, the coating spallation at the leading edge has a more serious influence on creep lifetime, which is more likely to cause the vanes failure. This study reveals the influence of coating spallation characteristics on the thermo-mechanical behaviors and creep lifetime of vanes, providing valuable insights for durability assessment of coated high-temperature components.

On the Initial Phase of the Ongoing Unrest at Campi Flegrei and Its Relation with Subsidence at Vesuvio (Italy)

The densely inhabited area of Naples (Italy), between the Campi Flegrei and Vesuvio volcanoes, is one of the most hazardous regions in the world. After two decades of sustained subsidence, Campi Flegrei has been experiencing an accelerating uplift since 2005. The uplift is currently associated with unusual seismicity and increased degassing. To try to identify the cause of the shift from subsidence to uplift and explore any connection between Campi Flegrei and Vesuvio, we analysed the ground displacement time series of the two volcanoes from 1993 to 2010, obtained from ERS/ENVISAT Synthetic Aperture Radar imagery. To distinguish between the various sources of deformation, we used simple scatter plots and a blind source separation technique called variational Bayesian independent component analysis (vbICA). We obtained consistent results using both approaches. Specifically, with vbICA, we identified two significant independent components (ICs). IC1 describes the subsidence that occurred at Campi Flegrei prior to 2000, including the mini-uplifts of 2000 and 2005, and part of the post-2005 uplift. The expansion and contraction of two volumes beneath Campi Flegrei satisfy IC1: a sill-shaped volume at a depth of approximately 3 km and a small volume at a depth of 1–2 km, respectively. The two sources of deformation reproduce the large-scale deformation in the Campi Flegrei area and the local deformation in the Solfatara area, respectively. In the Campi Flegrei area, IC2 exhibits primarily uplift, which is concentrated in the eastern part of the caldera. The deformation pattern is complex and difficult to interpret. If we model it using simple spheroidal deformation sources, the pattern suggests that two volumes at depths of approximately 9 and 8 km are experiencing opposite activity, namely contraction (beneath the southwestern part of the caldera) and expansion (beneath the central part of the caldera). In the Vesuvio area, IC2 is consistent with the deformation induced by the contraction of a volume at a depth of around 9 km. The contraction beneath Vesuvio is smaller in magnitude than the expansion/contraction beneath Campi Flegrei. The correlation observed after 2002 between uplift at Campi Flegrei and subsidence at Vesuvio suggests the transfer of magma and/or magmatic fluids between the two plumbing systems at 8–9 km depth. This implies that part of the ongoing unrest at Campi Flegrei may have been promoted by mass transfer from below Vesuvio.

Improved medium-to-short-term earthquake predictions in China in 2022

Every year, China should determine annual seismic hazard regions for earthquakes of magnitude 5.0 and above in Mainland China in the next year. Meanwhile, the short-term earthquake potential in each seismic hazard region is evaluated by monthly analyzing geophysical observations in the same neighborhood and identifying anomalies therein. In 2022, China improved the strategies for these medium-to-short-term earthquake predictions. The annual seismic hazard regions are produced with the optimal methods selected by rigorous tests whose predictions are integrated through the Bayesian formula. And in short-term earthquake potential evaluation, in addition to tracking crucial anomalies, China pays attention to the changes in the number of observed anomalies. The practice in 2022 shows that more than 80% of earthquakes of magnitude 5.0 and above in Mainland China occurred in annual seismic hazard regions. Besides, the largest (M s 6.9 Menyuan, Qinghai) and the most disastrous (M s 6.8 Luding, Sichuan) earthquakes were predicted in both annual and short terms. Some crucial anomalies were observed before these two earthquakes, whose evolutions correlate well with the earthquake time and location. The statistics of the near-field geophysical observations indicate that, prior to the mainshock, the number of anomalies increased significantly and migrated toward the epicenter.

In-event surrogate model training for regional transmission tower-line system dynamic responses prediction in realistic hurricane wind fields

Surrogate models have shown improved accuracy in predicting infrastructure responses during dynamic loadings. However, training a surrogate model for complex loading inputs across the entire hazard region remains challenging. This study provides insight into the training of surrogate models to estimate the responses of transmission tower-line structures in a coupled high-dimensional and high-resolution wind field and presents innovative methods for addressing these challenges. Four data- and physics-based spatial-temporal decoupling sampling methods are employed and cross-compared to obtain the most representative in-event wind profiles for training the surrogate model. Long Short-Term Memory (LSTM) is utilised as the surrogate model framework to predict the dynamic responses of the structure during the 2017 Hurricane Harvey. The accuracy and robustness of two transmission tower-line structure configuration surrogate models are validated by comparing the predictions with finite element analyses by using randomly distributed temporal and geospatial wind profiles throughout the hurricane. Finally, a single LSTM surrogate model is developed, trained by applying the full reference wind speed range of Hurricane Harvey for the regional-scale structural performance evaluation of the transmission tower-line system. The results demonstrate that the proposed surrogate model training methodology is general and can be applied to regional-scale structural performance evaluations.

From erosion to epidemics: Understanding the overlapping vulnerability of hydrogeomorphic hotspots, malaria affliction, and poverty in Nigeria

Hydrogeomorphic changes, encompassing erosion, waterlogging, and siltation, disproportionately threaten impoverished rural communities. Yet, they are often marginalized in discussions of disasters. This oversight is especially concerning as vulnerable households with limited healthcare access are most susceptible to related diseases and displacement. However, our current understanding of how these risks intersect remains limited. We explore the complex relationships between hydrogeomorphic hazards, malaria incidence, and poverty in Nigeria. Through spatial analyses we expand traditional boundaries, incorporating factors such as healthcare access, migration patterns, dam locations, demographics, and wealth disparities into a unified framework. Our findings reveal a stark reality: most residents in hydrogeomorphic hotspots live in poverty (earnings per person ≤$1.25/day), face elevated malaria risks (80 % in malaria hotspots), reside near dams (59 %), and struggle with limited healthcare access. Moreover, exposure to hydrogeomorphic hotspots could double by 2080, affecting an estimated 5.8 million Nigerians. This forecast underscores the urgent need for increased support and targeted interventions to protect those living in poverty within these hazardous regions. In shedding light on these dynamics, we expose and emphasise the pressing urgency of the risks borne by the most vulnerable populations residing in these regions—communities often characterised by limited wealth and resilience.

Unravelling vulnerabilities: mapping key hazards in the Gori Ganga watershed of Kumaon Himalaya for communication, conservation and management

The present study investigates the susceptibility of the Kailash Sacred Landscape in Uttarakhand's Pithoragarh district, focusing on regional-level disaster risk assessment in the Gori Ganga watershed as a case study and aims to prepare foundation maps for recurrent disasters like landslides, floods and forest fires. The techniques of remote sensing & geographic information systems, frequency ratio and correlation analytics were employed to perceive hazard-prone areas in the valley, using a variety of geographical, environmental and anthropogenic predictors. The accuracy of the maps generated by the modelling procedure was assessed using validation data and a receiver operating characteristics curve (ROC) with the area under the curve (AUC). The analysis revealed 83.5 km2 was extremely susceptible to flood incidents, 133.1 km2 was susceptible to landslides and 147 km2 was severely vulnerable to wildfires. The determined area under the curve value for flood susceptibility was 88.6%, followed by landslides at 89.5% and wildfires at 90.9%, showing that the model performed exceptionally well. The findings reveal that precipitation, lithology and elevation were the most significant variables in inducing floods. Precipitation, profile curvature, elevation and distance to thrust are the primary determinants of landslides, while closeness to the road and settlements, as well as vegetation indices, were significant predictors of fire events. The Lower Kumaon Himalayan valley region was recognized as highly vulnerable to all three major catastrophes. This study identifies potentially hazardous regions for adaptive sustainable conservation activities, involving local communities in decision-making to mitigate impacts and aid in preventing and managing impending landscape-level threats.

Fatigue reliability and sensitivity analysis of aero‐disk considering correlation

AbstractAero‐disk is a key component of aero‐engine. Due to its complex working conditions, aero‐disk is prone to structural failures. Therefore, it is essential to analyze the reliability and importance input variables of aero‐disk. In this paper, a framework of aero‐disk reliability analysis and global sensitivity analysis (GSA) was established. First, the hazardous regions of aero‐disk were determined by finite element analysis, and the limit state function of aero‐disk was defined by the life interference model. Then D‐Vine model was utilized to establish the correlation model for aero‐disk hazardous regions to evaluate the reliability of aero‐disk. In addition, two GSA methods based on Copula and space partition were proposed to identify important input random variables considering underlying correlation, and the accuracy of the proposed method was verified by two examples. Finally, the proposed method was applied to the GSA of aero‐disk. The results show that the established framework fills in the gap of uncertainty analysis of aero‐disk, which can be extended to other engineering fields. The proposed GSA methods have both high efficiency and accuracy and can realize multi‐dimensional GSA when the correlation of input variables is considered.

Device-to-device based path selection for post disaster communication using hybrid intelligence

Public safety network communication methods are concurrence with emerging networks to provide enhanced strategies and services for catastrophe management. If the cellular network is damaged after a calamity, a new-generation network like the internet of things (IoT) is ready to assure network access. In this paper, we suggested a framework of hybrid intelligence to find and re-connect the isolated nodes to the functional area to save life. We look at a situation in which the devices in the hazard region can constantly monitor the radio environment to self-detect the occurrence of a disaster, switch to the device-to-device (D2D) communication mode, and establish a vital connection. The oscillating spider monkey optimization (OSMO) approach forms clusters of the devices in the disaster area to improve network efficiency. The devices in the secluded area use the cluster heads as relay nodes to the operational site. An oscillating particle swarm optimization (OPSO) with a priority-based path encoding technique is used for path discovery. The suggested approach improves the energy efficiency of the network by selecting a routing path based on the remaining energy of the device, channel quality, and hop count, thus increasing network stability and packet delivery.

Framework for the design of seismically isolated National Building Code of Canada Part 9 structures

In Canada, most single-family wood-frame residential structures in seismically hazardous regions are constructed according to Part 9 of Division B of the National Building Code (or similar provincial standards) using nonengineering methods. These structures are expected to perform well during an earthquake regarding life safety but may sustain severe economic losses. Seismic isolation is an emerging technology that provides excellent life safety and economic performance. While this technology has proven effective at protecting structures from earthquakes, no nonengineering methodologies exist that are compatible with Part 9 methods. This limitation produces significant testing, design, and cost barriers that restrict the application of base isolation on vulnerable Part 9 structures. To eliminate or reduce these cost barriers, a program framework was developed to perform the engineering seismic design and analysis for a base-isolated Part 9 single-family residential structure. The proposed methodology further encourages the application of seismic isolation to Part 9 structures.

Research on the coupled support technology of a composite rock beam-retained roadway roof under close coal seams

IntroductionThe technology of gob-side entry retaining without coal pillars in close (distance) coal seams is still immature, and the roof control and support technology in this case is not perfect.MethodsIn this paper, the coupled support technology of a composite rock beam roof under close coal seams is systematically studied by using theoretical analysis, numerical simulation and field test.ResultsBoth the floor slip calculation results and numerical simulations indicate that the vertical failure depth in the plastic zone of the #8 coal seam has not penetrated the roof of the #9 coal seam after mining, which is consistent with the field electronic imaging results. A theoretical formula for a composite rock beam model anchored by high-prestressed anchor cables was derived, and a formula for the optimal spacing of anchor cables under noncompressive shear failure of the roof was obtained. Identification of the internal stress hazard region of the rock beam provides a basis for determining the locations of vertical support. Through numerical simulation of different support schemes, including roof cutting, arrangement of high-prestressed anchor cables, and setting up of vertical supports, roof cutting was found to effectively reduce the stress of supporting structure and roof pressure. Setting up of vertical supports can reduce the roof convergence by 25.2%, and coupling with anchor cables can reduce the convergence by more than 49.1%. The feasibility of this support scheme was verified through field tests, with a maximum convergence of 99 mm between the roof and floor.DiscussionThis two-way verification approach, in which the damage degree of the roof of a close coal seam is analyzed through multiple means, targeted support plans are proposed, the support mechanisms are explored, and feedback is conducted through field tests, plays a certain guiding role in solving roof control of the gob-side entry retaining under similar geological conditions.

Tsunami-driven debris hazard assessment at a coastal community: Focusing on shipping container debris hazards at Honolulu Harbor, Hawaii

A framework combining a tsunami flow model and debris (large floating object) transport model was developed to evaluate the kinematics of multiple debris and sequential hazards in a coastal community. We derive the analytic solution of the semi-analytic model of debris transportation, and adapt to evaluate the impact of tsunami-driven debris at Honolulu Harbor, Hawaii as a case study by simulating the motion of 2500 shipping containers under a hypothetical 2500-year tsunami event. The study provides a framework for assessing tsunami-driven debris hazards in a coastal community by introducing new types of intensity measures for tsunami-driven debris hazards. The final debris dislocation in the numerical debris transport model was quantitatively compared with the debris impact hazard region of the ASCE 7–22 method. This study introduces new types of hazard maps showing the intensity ratios of the debris dispersion, maximum impact loading, accumulated impact loading, and 5% exceedance impact loading. These new hazard maps characterize the potential impact loadings from debris dispersion on a community scale and display hotspots that show the strong intensity of the hazards from debris. The sensitivity of the new hazard maps based on the debris model parameters is also discussed.

Remote sensing as a tool for natural disaster risk analysis: a bibliometric review

Introduction: remote sensing as a tool is a fundamental resource that helps to develop various applications for disaster risk management.Objective: to conduct a bibliometric analysis of remote sensing as a tool for natural disaster risk analysis in Scopus between 2003 and 2023.Methods: this was a bibliometric analysis that defined the metrics of scientific production. The indicators were obtained from 409 documents chosen from the Scopus database using keywords in English (Remote sensing, natural disaster).Results: the data revealed a significant increase in the number of papers published on the topic (59,9 %) between 2019 and 2023. In addition, China (22,5 %; n=133) recorded the highest rate of scientific output, with the Chinese Academy of Sciences publishing the most (n=36). The journal Remote Sensing published 30 papers, while Natural Hazards received 720 citations, the most referenced author being Pradhan, B. (n=11 papers; 1587 citations).Conclusions: studies on this topic have increased in number, subject variation and author cooperation, as remote sensing allows data to be collected from inaccessible or hazardous regions, enabling real-time monitoring and tracking of natural phenomena.

MODELLING OF DEBRIS MOTION DRIVEN BY TSUNAMI WAVE BREAKING

When a giant tsunami approaches onshore, offshore vessels and other floating objects move following the current of the tsunami. Some of the waterborne debris are transported to tsunami inundation areas and those debris impact buildings. For evaluations of debris impact loads, types of debris having the potential to impact and damage the structures are identified by considering debris impact hazard region. According to ASCE7-22, the debris impact hazard region shall be determined by the empirical model proposed by Naito et al. (2014) in a simple manner. Furthermore, numerical debris transport modelling using massless tracers also shall be permitted to use for the determination. On the other hand, numerical debris tracking (nDT) modellings which solve the equation of motion of debris have been developed (e.g., Kihara and Kaida, 2019). In this study, a surface roller modelling is incorporated into the nDT model of Kihara and Kaida (2019) to simulate debris motions driven by tsunami wave breaking. To validate the model, simulations of hydraulic experiments focusing on the motion of offshore debris reported by the Nuclear Regulation Authority (NRA) of Japan are carried out (Oda et al., 2021).

Earthquakes in Turkey and Syria in 2023 and geodynamics of the Caucasus-Anatolian region

Background. The intensification of natural disasters all over the world requires the development of new approaches to the study of geological processes. This particularly concerns the areas at the boundaries of lithospheric plates, which are characterized by earthquakes, increased seismicity, volcanism, intensive heat flows, geothermal manifestations, landslide processes, tsunamis, and other dangerous natural processes and hazards. The Caucasus-Anatolian-Arabian region is a complex highly-stressed geodynamic structure, characterized by an increased heat flow, seismicity, magmatism, and volcanism. The geodynamics of this region is determined by the collision of the Eurasian and Arabian lithosphere plates, as well as by the evolution of the Alpine-Himalayan belt and surrounding areas. A 7.8 magnitude earthquake hit the South-East Turkey and North-West Syria on February 6, 2023. This was the largest earthquake in Turkey since the 1939 Erzincan earthquake, and the second-strongest since the 1668 North Anatolia earthquake. More than 52,800 deaths were confirmed, with about 46,100 in Turkey and 6,700 in Syria. It is the deadliest natural disaster in Turkey’s modern history with the estimated damage of over $100 billion. Aim. To construct geodynamic models for the deep structure of natural hazard regions, which can contribute to the study of active continental margins. This information is necessary for earthquake forecasting and prognosis, as well as for assessing geoecological risks and preparing the population in the event of natural disasters and catastrophes. Materials and methods. The formation and evolution processes of geological structures in complex geodynamic settings, as well as the forecasting and prognosis of natural hazards, required an analysis of all available geological and geophysical data. The methods of mechanical and mathematical modeling were used to formulate and solve the research problems. Results. Geodynamic models of the regions of hazardous natural processes were constructed with the purpose of forecasting and preventing natural disasters and catastrophes. An algorithm for creating monitoring systems was proposed. Conclusion. In several years (1–10 years), another earthquake near Istanbul can be expected. In the case that no large earthquake occurs in the East Anatolian fault in 1–2 years, this event is likely to occur in 100 years only.

Performance-based Analysis of Building Structures in Various Earthquake Zones

The structural design of an eight-story building was examined to determine its performance in resisting ultimate loads. This was necessary for applying the building design in Indonesian regions with low to high seismic hazard levels. Studies have indicated that pushover analysis is suitable to assess the capacity of building structures against earthquake loads. However, as the structural design of each building produces its nominal strength, performance analysis must always be conducted. This study aimed at comparing the structural performance of buildings in regions with low, medium, and high seismic hazards, represented by the cities of Palembang, Jakarta, and Palu, respectively. A performance-based analysis was conducted using the pushover method to obtain the performance points. The responses of the building structures were the base shears, floor drifts, and inter-story drifts. The structural performance levels in the three regions were between immediate occupancy and life safety or were categorized as damage control, indicating minor damage. Because the structures exhibited high stiffness and ductility, they resisted the ultimate forces up to the damage control performance level in all regions. The greatest lateral drifts of 79.744 mm and 51.656 mm in the X- and Y-axis directions, respectively, occurred in Palu’s high seismic hazard region. The lowest lateral drift occurred in Palembang’s low seismic hazard region, in the X- and Y-axis directions of 59.401 mm and 38.378 mm, respectively.

Recommendations for seismic analysis of a molten salt reactor

A Fluoride-salt cooled High-temperature Reactor (FHR) that uses circulating solid TRISO pebbles, as a fuel and positively buoyant graphite reflector blocks as a moderator is at an advanced stage of development. Seismic base isolation supports a pathway for cost competitive and rapid deployment of this molten salt reactor (MSR) in regions of different seismic hazard. This paper presents recommendations for analysis and modelling of different components of a base-isolated MSR, based on results of earthquake-simulator tests on a scale model of the reactor. Recommendations are provided for evaluating the sloshing behavior of the coolant in an annular region inside the reactor and for estimating hydrodynamic loads for use in analysis of structural and mechanical components. Hydrodynamic loading on the reflector blocks is discussed and a practical approach to estimate forces in the connections between them is presented. Approaches for modelling and analysis of two 2D horizontal base-isolation systems, utilizing spherical sliding bearings, are validated using results from experiments. The recommendations apply to reactor vessels with similar fluid-structure systems.

Learning from the Past: Parametric Analysis of Cob Walls

In this paper, the results obtained from a series of parametric analyses, where the influence that geometric and mechanical parameters have in the structural response of existing vernacular cob walls within an Irish context, are presented. A design of experiments using central composite designs was implemented along with analysis of variance following two computational approaches, namely, the finite element method and kinematic limit analysis. As results, a series of response surfaces and parametric equations with which it is possible to compute safety factors and collapse multipliers (within the range of values studied) are provided. Based on the results obtained, it could be concluded that traditional cob walls in Ireland are very robust. Relatively high acceleration values, unlikely to happen in a low seismic hazard region such as Ireland, would be needed to start the collapse mechanisms studied or cause yielding in typical vernacular cob walls. Furthermore, the equations generated with the refined regression models can be used by practitioners as a first approach to estimate the safety levels of existing cob buildings with similar characteristics.

Assessing Coastal Vulnerability to Storms: A Case Study on the Coast of Thrace, Greece

Climate change is expected to increase the risks of coastal hazards (erosion and inundation). To effectively cope with these emerging problems, littoral countries are advised to assess their coastal vulnerabilities. In this study, coastal vulnerability is first assessed by considering two basic storm-induced phenomena, i.e., erosion and inundation. First, the erosion is computed using the numerical model for Storm-induced BEAch CHange (SBEACH), whereas the inundation is estimated using two different empirical equations for comparison. Then, the integration of the vulnerabilities of both storm-induced impacts associated with the same return period permits the identification of the most hazardous regions. The methodology is applied to the coast of Thrace (Greece). The majority of the coastline is not vulnerable to erosion, except for some steep and narrow beaches and the coast along the city of Alexandroupolis. Beaches with very low heights are highly vulnerable to inundation. Half of the studied coastline is considered highly or very highly vulnerable, whereas the other half is relatively safe. The above results will help decision-makers choose how to invest their resources for preventing damage.